I used hq/hj holden u bolts on mine. Cost $50 new for the pair and fitted perfect just need to trim them down a bit

I bought mine from king springs. Good quality. Expensive. Used 75mm ones too fit the diff housing and they did need trimming. And where m10 so didn't have too drill the backing plate. The #OOPS#ty lowering block kits use imperial I think so needs too drill the backing plate out. And the u bolts stretch alot. Can't ever seem too get a firm tension. The kings spring u bolts where High tensile so didn't stretch alot and tensioned up well.

Hit the wreckers and chase up some U bolts and nuts from a ford falcon Ute.
They too have a Borg Warner diff therefore the axel tubes are the same thickness / diameter. They will be more than long enough; you will probably end up having to cut a bit of length off, if anything.

Need a set of U bolts for R31 diff conversion. What are people using? Is there something you can buy off the shelf that fits?

Been told locally that they need to be made up, but at $30 each that aint cheap.

Was thinking ea falcon or earlier falcons?

Cheers